pub fn new_birthday_probability(n: u32) -> f64 {
    let p: f64 = 1.0;

    let subp = (1..n)
        .map(|i| (365.0 - i as f64) / 365.0)
        .fold(p, |acc, x| acc * x);

    // 仅保留四位小数
    ((1.0 - subp) * 10000.0).round() / 10000.0
}
